Polaroids And Karo Syrup

Purpose

Beautiful and simple demonstration of optical activity.

Equipment

Goose neck lamp with 100 watt bulb, rotating polaroids on base, bottle of Karo syrup with label removed.

Images

m8-01

Description

Place a glass bottle of Karo syrup between two crossed polaroids lighted from behind, then rotate one of the polaroids. The second polarizing sheet removes a small band around one wavelength of light, to produce beautiful negative colors. This is a breathtaking experiment for those seeing it the first time. A must with this topic. See the Feynman Lectures text for a nice explanation.

References

W. P. Healy and E. A. Power, Dispersion Relations for Optically Active Media, AJP 42, 1070-1074 (1974). R. M. Peterson, Comparison of two theories of optical activity, AJP 43, 969-972 (1975).